Videnskabelige meddelelser

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Videnskabelige meddelelser

136

Muller's specimens had the point of the postero-iateral arms red

coloured (and, judging from his figure, quite conspicuously so), and

the young star also had a big red patch in the middle of the

dorsal side ; the specimens observed by me had only a faint yel-

lowish tint in the end of the arms and in the middle of the dorsal

side of the young star, the larva being otherwise niilky white

and opaque, so that the skeleton could not be seen distinctly

without applying some clearing fluid. This diversity in colour

being the only notable difference between the two larvæ it seems

justifiable to regard them as identical or, at least, as belonging to

two very closely related species. The faet that there were no dis-

tinet ciliated bands along the postero-iateral arms, together with

the peculiar opaqueness of the larva, would seem to indicate that

this larva does not have the full pluteus shape, but belongs to

the rudimentary larva! forms. This cannot, however, be decided,

before larvæ have been observed in which the metamorphosis is

less advanced than in those observed till now.

The occurrence of this larval form both in the Adriatic and at the

coast of Bohusian allows a suggestion about the Ophiuroid to which

it must belong. The following Ophiuroids are common to the Scan-

dinavian seas and the Adriatic: Ophiiira teæturaia, O. albida, O.

(iffinis, Amphiura filiformis, A. Chiajei, Aniphipholis squamata,

Ophiothrix fragilis and probably also Ophiocoma nigra. Of these

species one, Amph. squamata, is viviparous and thus cannot come

into consideration. The larvæ of Ophiiira teæturata, O. albida, Am-

phiura filiformis (see below) and Ophiothrix fragilis are known,

these species being thus also eliminated ; likewise Ophiocoma ni-

gra, evidently, is out of question.') Amphiura Chiajei and Ophiura

affmis thus alone can come into consideration as species to which

this larva could belong. Joh. Muller, in faet, suggested that the

larva might possibly belong to Amphiura Chiajei (he names it

incorrectly Ophiolepis SiindeDalli; as it is especially noticed that

the species has two tentacle scales, it is beyond doubt that the

species meant is Amph. Chiajei), his reason for this suggestion

being that the dorsal side of the disk in this species is red as in

') Th. M orte n se n. On the development of some British Echinoderms.

Journ. Mar. Biol. Assoc. N. Ser. X. 1913. p. 12.

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